3^х+2+2*3^х+1=405 eto so stepenjami

Question

3^х+2+2*3^х+1=405 eto so stepenjami

Answer 1

3^(x+2)+2*3^(x+1)=405

3^2*3^x+2*3*3^x=405

9*3^x+6*3^x=405

15*3^x=405

3^x=405:15

3^x=27

3^x=3^3

x=3